US main contributor to deluge of plastic waste

chaired the NAS committee.

The researchers estimated that between 1.13 million to 2.24 million tonnes of the US’S plastic waste end up in the environment each year. About 8 million tonnes of plastic end up in the ocean each year, and under the current trajectory this could climb to 53 million tonnes by the end of the decade.

That amount of waste would be the equivalent to ‘‘roughly half of the total weight of fish caught from the ocean annually’’, the report said.

The US Environmental Protection Agency recently released a national recycling strategy, which critics faulted for not taking aim at the current level of plastics production. The new report said current recycling systems were ‘‘grossly insufficient to manage the diversity, complexity, and quantity of plastic waste in the United States’’.

– Washington Post

Prehistoric footprints that have puzzled scientists since the 1970s are getting a second look: were they left by extinct animals or by human ancestors?

When famed palaeontologist Dr Mary Leakey uncovered the footprints in Tanzania 40 years ago, the evidence was ambiguous.

Leakey focused her attention instead on other fossil footprints that could be more clearly linked to early humans. Those footprints, found at a site called Laetoli G, are the first clear evidence of early humans walking upright.

Decades later, a new team reexcavated the confusing footprints, found at a site called Laetoli A, and made photos and 3D scans available for other researchers to continue the debate. The research has been published in the journal Nature.

What has long perplexed scientists is that the tracks – broad footprints with enlarged fifth toes, and estimated to be around 3.7 million years old – don’t closely match anything scientists have elsewhere identified.

‘‘They didn’t have the right weight and foot movement to be easily identified as human, so other explanations were sought,’’ including that they may belong to an extinct species of bear, said